import cv2

import numpy as np

import matplotlib.pyplot as plt

# Affine

def affine(img, a, b, c, d, tx, ty):

H, W, C = img.shape

# temporary image

img = np.zeros((H+2, W+2, C), dtype=np.float32)

img[1:H+1, 1:W+1] = _img

# get new image shape

H_new = np.round(H * d).astype(np.int)

W_new = np.round(W * a).astype(np.int)

out = np.zeros((H_new+1, W_new+1, C), dtype=np.float32)

# get position of new image

x_new = np.tile(np.arange(W_new), (H_new, 1))

y_new = np.arange(H_new).repeat(W_new).reshape(H_new, -1)

# get position of original image by affine

adbc = a * d - b * c

x = np.round((d * x_new - b * y_new) / adbc).astype(np.int) - tx + 1

y = np.round((-c * x_new + a * y_new) / adbc).astype(np.int) - ty + 1

x = np.minimum(np.maximum(x, 0), W+1).astype(np.int)

y = np.minimum(np.maximum(y, 0), H+1).astype(np.int)

# assgin pixcel to new image

out[y_new, x_new] = img[y, x]

out = out[:H_new, :W_new]

out = out.astype(np.uint8)

return out

# Read image

_img = cv2.imread("imori.jpg").astype(np.float32)

# Affine

out = affine(img, a=1.3, b=0, c=0, d=0.8, tx=30, ty=-30)

# Save result

cv2.imshow("result", out)

cv2.waitKey(0)

cv2.imwrite("out.jpg", out)